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add movegen draft, add king square in pos_t, BRQKN move gen (untested)

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Bruno Raoult
2024-02-20 21:00:45 +01:00
parent 403e625cbe
commit 568b39e366
11 changed files with 231 additions and 53 deletions
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58
src/hyperbola-quintessence.c
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@@ -30,15 +30,29 @@ uchar bb_rank_attacks[64 * 8];
* See: https://www.chessprogramming.org/Kindergarten_Bitboards
* and https://www.chessprogramming.org/Hyperbola_Quintessence
*
* Generate the rank attacks bitboard:
* bb_rank_hyperbola[64 * 8], where:
* - 64 = 2^6 = the occupation of inner 6 bits on rank
* - 8 = file of sliding piece
*
* Rank attacks table:
* bb_rank_hyperbola[512 = 9 bits], indexed by oooooofff where:
* - O = oooooo: occupation of inner 6 bits on rank
* - F = fff: file of sliding piece
* The index is built as (oooooo << 3 + fff), = ((O << 3) + F), where:
* - O = all combinations of 6 bits (loop from 0 to 64)
* - F = all files (loop from 0 to 7)
* To retrieve the index, given an 8 bits mask M=XooooooX, and a file F=fff,
* we get O from M with:
* 1) remove bits 'X' (O = M & 01111110)
* 2) shift left result 2 more bits, as bit 0 is unused and already cleared:
* (O <<= 2)
*
* TODO ? create masks excluding slider (eg. bb_diagonal ^ bb_sq[square]),
* to save one operation in hyperbola_moves().
* TODO ? replace rank attack with this idea, mapping rank to diagonal ?
* See http://timcooijmans.blogspot.com/2014/04/
*
*/
void hyperbola_init()
{
/* generate rank attacks
/* generate rank attacks, not handled by HQ
*/
for (int occ = 0; occ < 64; ++occ) {
for (int file = 0; file < 8; ++file) {
@@ -48,7 +62,7 @@ void hyperbola_init()
for (int slide = file - 1; slide >= 0; --slide) {
int b = bb_sq[slide]; /* bit to consider */
attacks |= b; /* add to attack mask */
if ((occ << 1) & b) /* piece on b, we stop */
if ((occ << 1) & b) /* piece on b, we stop */
break;
}
/* set f right attacks */
@@ -63,6 +77,24 @@ void hyperbola_init()
}
}
/**
* hyperbola_rank_moves() - generate rank moves for a sliding piece.
* @pieces: occupation bitboard
* @sq: piece square
*
* Rank attacks are not handled by HQ, so we do it with a
*
* @Return: The moves mask for piece
*/
static bitboard_t hyperbola_rank_moves(bitboard_t occ, square_t sq)
{
uint32_t rank = sq & SQ_FILEMASK;
uint32_t file = sq & SQ_RANKMASK;
uint64_t o = (occ >> rank) & 0x7e; /* 01111110 clear bits 0 & 7 */
return ((bitboard_t)bb_rank_attacks[o * 4 + file]) << rank;
}
/**
* hyperbola_moves() - generate hyperbola moves mask for a given sliding piece
* @pieces: occupation bitboard
@@ -80,19 +112,9 @@ static bitboard_t hyperbola_moves(const bitboard_t pieces, const square_t sq,
bitboard_t r = bswap64(o);
square_t r_sq = FLIP_V(sq);
return ( (o - mask(sq) )
^ bswap64(r - mask(r_sq)))
return ( (o - 2 * mask(sq) )
^ bswap64(r - 2 * mask(r_sq)))
& mask;
}
static bitboard_t hyperbola_rank_moves(bitboard_t occ, square_t sq)
{
uint32_t rank = sq & SQ_FILEMASK;
uint32_t file = sq & SQ_RANKMASK;
uint64_t o = (occ >> rank) & 126; /* removes bits 0 & 7 */
return ((bitboard_t)bb_rank_attacks[o * 4 + file]) << rank;
}
static bitboard_t hyperbola_file_moves(bitboard_t occ, square_t sq)